1. Field of the Invention
The present invention relates to an electronic component and a production method thereof. More specifically, the present invention relates to an electronic component such as a surface mount type inductor or strip line component, or other similar component, which is to be mounted on the surface of a pattern of a printed circuit board, and a production method thereof.
2. Description of the Related Art
A method of manufacturing a surface mount type inductor having a high Q value includes forming a coil conductive pattern on a ceramic mother substrate by a screen printing process with a large coil conductive pattern film thickness (large cross-sectional area) for having a small coil conductive pattern direct current resistance value (conductor loss) is commonly known. However, according to this screen printing method, the size of the coil conductive pattern is extremely irregular in terms of the accuracy. In addition, the deviation of the inductance values is large and it is difficult to have a narrow conductor width for the coil conductor.
On the other hand, as a method of manufacturing an inductor with a small inductance value deviation, a method of forming a metal film on a mother substrate via sputtering, deposition, or the like, and forming a coil conductor pattern using photolithography technology is commonly known. However, according to this method, it is difficult to have a thick coil conductor pattern thickness compared with the screen printing method, and thus, it is difficult to produce an inductor with a high Q value.
Then, as a method of producing an inductor with a high Q value and a small inductance value deviation, a method of forming a coil conductor pattern including a combination of thick film printing and photolithography technology, using a photosensitive conductive paste, and a method of forming a coil conductor pattern with a thick film and a high size accuracy via a method referred to as a semi-additive process have been proposed (see, for example, the Official Gazettes of Japanese Unexamined Patent Publication Nos. 8-316080 and 945570).
However, due to a high production cost caused by a large number of manufacturing and processing steps required by the semi-additive process, a method of using a photosensitive conductive paste is preferable. However, in order to obtain a small size inductor having a large inductance value, a very small size coil conductor pattern must be formed within a limited coil conductor forming area. Therefore, even in the case of using a photosensitive conductive paste in the conventional method, a problem occurs in that the line width of the coil conductor pattern becomes small so as to have a large conductor loss, and thus, the Q value is lowered. Moreover, since the limit of the resolution of a photosensitive conductive paste in the thickness direction has an aspect ratio of 1 (after development), it is difficult to have a thicker photosensitive conductive paste film. The aspect ratio of a coil conductor pattern is defined as the ratio of the thickness to the pattern width of a coil conductor pattern.